Using big data to explore worldwide trends in objective sleep in the transition to adulthood

Background: Development induces changes in sleep, and its duration has been reported to change as a function of aging. Additionally, sleep timing is a marker of pubertal maturation, where during adolescence, the circadian rhythm shifts later. Typically, this is manifested in a later sleep onset in the evening and later awakening in the morning. These changes across development seem to be universal around the world but are unlikely to persist into adulthood. Methods: This study utilized accelerometer data from 17,355 participants aged 16-30 years (56% female) measured by validated Polar wearables over a 14-day period. We compared sleep duration, chronotype (sleep midpoint) and weekend catch-up (ie, social jetlag) sleep across ages and regions over 242,948 nights. Results: The data indicate a decline in sleep duration as well as a dramatic shift in sleep onset times throughout adolescence. This continues well into early adulthood and stabilizes nearer age 30. Differences in sleep duration across ages were significant, and ranged from 7:53 h at age 16 to 7:29 h at age 30 in the sample. Additionally, there was a clear difference between females and males throughout adolescence and young adulthood: girls had longer sleep duration and earlier timed sleep in the current study. Differences in sleep were found between regions across the world, and across European areas. Conclusions: Both sleep duration and sleep timing go through a clear developmental pattern, particularly in early adulthood. Females had an earlier sleep midpoint and obtained more sleep. Regional differences in sleep occurred across the world. Crown Copyright (C) 2019 Published by Elsevier B.V. All rights reserved.Peer reviewe

Incidence and Severity of Sexual Harassment, and its Impact on Mental Health in a Cohort of International Humanitarian Field-Workers

To date, there have been no cohort studies of sexual harassment incidence and its relation to mental health within humanitarian field-workers. Research among numerous occupations suggests an association between workplace sexual harassment and several health complaints. This study examined the incidence and severity of sexual harassment and its association with changes in mental health in a cohort of international humanitarian aid field-workers (iHAWs). Four hundred and seventy-eight iHAWs filled in questionnaires about sexual harassment, depression, anxiety, and Post-Traumatic Stress Disorder (PTSD) as part of a larger study on health and well-being. Six percent of male and 18% of female iHAWs reported experiencing sexual harassment during their latest field assignment, with most reporting low levels of nonphysical forms of sexual harassment. Sexual harassment was predictive of negative changes in both depression and anxiety symptom severity between before and after an assignment for females; for males, it predicted negative changes in PTSD symptom severity. Sexual harassment did not predict utilization of mental healthcare services within 2 months after the end of assignment. The current findings are the first figures derived from a representative sample of iHAWs on the incidence of sexual harassment during a field assignment and show sexual harassment to be a relatively common and present issue. The findings are mostly in line with the extant literature and underscore the importance of attending to the issue of sexual harassment in the humanitarian sector

Health trajectories of international humanitarian aid workers: growth mixture modelling findings from a prospective cohort study

Background  Most staff stay healthy during humanitarian work, although some worsen. Mean scores on health indicators may be masking individual participants struggling with health issues. Aims To investigate different field assignment-related health trajectories among international humanitarian aid workers (iHAWs) and explore the mechanisms used to stay healthy.  Method  Growth mixture modelling analyses for five health indicators using pre-/post-assignment and follow-up data.  Results  Among 609 iHAWs three trajectories (profiles) were found for emotional exhaustion, work engagement, anxiety and depression. For post-traumatic stress disorder (PTSD) symptoms, four trajectories were identified. The 'healthy/normative' trajectory had the largest sample size for all health indicators (73-86%). A stable (moderate) 'ill health' trajectory was identified for all health indicators (7-17%), except anxiety. An 'improving' trajectory was found for PTSD and anxiety symptoms (5-14%). A minority of staff (4-15%) worsened on all health indicators. Deterioration continued for PTSD, depressive symptoms and work engagement 2 months post-assignment. A strong sense of coherence was associated with higher odds of belonging to the 'healthy' trajectory. Female biological sex was associated with higher odds of belonging to the 'worsening' depression and anxiety trajectories. Extended duration of field assignment was related to higher odds of belonging to the 'worsening' depressive symptoms trajectory.  Conclusions  Most iHAWs stayed healthy during their assignment; a stable 'ill health' trajectory was identified for most health indicators. Sense of coherence is an important mechanism for understanding the health of all iHAWs in the different health trajectories, including the 'healthy' profile. These findings give new possibilities to develop activities to prevent worsening health and help strengthen iHAWs' ability to remain healthy under stress

Heart rate dynamics after combined strength and endurance training in middle-aged women: Heterogeneity of responses.

The loss of complexity in physiological systems may be a dynamical biomarker of aging and disease. In this study the effects of combined strength and endurance training compared with those of endurance training or strength training alone on heart rate (HR) complexity and traditional HR variability indices were examined in middle-aged women. 90 previously untrained female volunteers between the age of 40 and 65 years completed a 21 week progressive training period of either strength training, endurance training or their combination, or served as controls. Continuous HR time series were obtained during supine rest and submaximal steady state exercise. The complexity of HR dynamics was assessed using multiscale entropy analysis. In addition, standard time and frequency domain measures were also computed. Endurance training led to increases in HR complexity and selected time and frequency domain measures of HR variability (P<0.01) when measured during exercise. Combined strength and endurance training or strength training alone did not produce significant changes in HR dynamics. Inter-subject heterogeneity of responses was particularly noticeable in the combined training group. At supine rest, no training-induced changes in HR parameters were observed in any of the groups. The present findings emphasize the potential utility of endurance training in increasing the complex variability of HR in middle-aged women. Further studies are needed to explore the combined endurance and strength training adaptations and possible gender and age related factors, as well as other mechanisms, that may mediate the effects of different training regimens on HR dynamics.peerReviewe